Re: Need help debugging SIGBUS crashes

On Tue, Mar 17, 2026 at 02:40:24PM +0100, Tomas Vondra wrote:
! I agree it's hard to deduce anything from the backtraces with the
! interesting bits optimized out. Rebuilding the OS with -O0 might be an
! overkill, I'd probably start by building just Postgres. That'd at least
! give us some idea what happens there, you could inspect the memory
! context etc.
!
! I'm not a FreeBSD expert, but this seems a bit suspicious:
!
! frame #23: 0x0000000822ae79b6
! libthr.so.3`handle_signal(actp=0x0000000820c5c600, sig=30,
! info=0x0000000820c5c9f0, ucp=0x0000000820c5c680) at thr_sig.c:318:3
! frame #24: 0x0000000822ae6eba libthr.so.3`thr_sighandler(sig=30,
! info=0x0000000820c5c9f0, _ucp=0x0000000820c5c680) at thr_sig.c:261:2
!
! I mean, libthr seems to be a 1:1 with pthreads. Are you using threads in
! some way? Perhaps an extension using threads? That could cause weird
! failures, including weird SIGBUS ones.

Hi, thanks for noting this - I didn't look that far up the stack.

The only extensions in this specific cluster are pg_freespacemap and
plpgsql. Others may have hstore and plpython3u.

I have currently no clue where this could come from, but will keep
it in mind. Thank You for noticing it.

PMc